Unfortunately I'm not able to get this to work, i suspect the device WAX220 is not fully compatible with the current stable openwrt, at least some features do not seem to work yet. For example I'm also experiencing slow upload speeds like described in this post (also a netgear wax2.. series) WAX206 Slow Upload Speeds
The device is stable but there must be something not fully compatible, I'll try the snapshot this week which is from the 22 of Jan to see it that helps. Thanks for the help so far an will keep you posted.